1. Field of the Invention
The present invention relates to a camera apparatus and lens control interface apparatus and more particularly, to a camera apparatus and a lens control interface unit to be connected to a control unit used for a DC motor-type lens unit and capable of operating a lens mechanism provided with a pulse signal drive motor.
2. Description of the Prior Art
Conventionally, a DC motor has been used in a camera apparatus having a zoom lens mechanism such as a video camera for controlling zoom, focus, iris and the like. Such a camera apparatus has been widely used in an image pickup system for monitoring, for example, in a bank, shop, parking area, and the like. Hereinafter, an explanation will be given of an image pickup system using a conventional camera apparatus with reference to FIG. 1 and FIG. 2.
As shown in FIG. 1, a conventional image pickup system 100 includes: a camera unit 110 consisting of a zoom lens block 120 having a zoom lens (not depicted) operated by a DC motor and a pickup signal generation block 130 having an image pickup element 131 and an image processing circuit 132; and a camera control unit 140 for controlling the zoom lens block 120 of this camera unit 110. In this conventional image pickup system 100, the zoom lens of the camera unit 110 is remote controlled from the camera control unit 140 for zooming, focusing, and iris operation as well as zoom and focus preset operation.
The camera unit 110 is installed, for example, at a predetermined position for monitoring clients of a bank. In the camera unit 110, an image pickup light from the zoom lens arranged in this zoom lens block 120 is received by an image pickup element 131 such as a CCD arranged in the pickup signal generation block 130, whose output is supplied to the image processing circuit 132, which in turn generates a pickup signal.
The pickup signal is supplied via a coaxial cable or the like to the camera control unit 140. The camera control unit 140 can control the display of a monitor image on a image display unit (not depicted) and the recording of a pickup signal on a VTR apparatus.
The zoom lens block 120 of the camera unit 110 includes the aforementioned zoom lens, a zoom position adjustment mechanism (not depicted) for adjusting a zoom position, and a zoom DC motor 121 which is connected to this zoom position adjustment mechanism. The zoom DC motor 121 is connected to a zoom DC motor drive circuit 143 of the camera control unit 140, so as to be operated by a zoom DC motor drive voltage signal 140a outputted from this drive circuit 143.
Moreover, the zoom lens block 120 includes a focus position adjustment mechanism (not depicted) for adjusting a focus position of the aforementioned zoom lens and a focus DC motor 122 connected to this focus position adjustment mechanism. This focus DC motor 122 is connected to a focus DC motor drive circuit 144 of the camera control unit 140 which will be explained later, so as to be operated by a focus DC motor drive voltage signal 140b outputted from this drive circuit 144.
Furthermore, the zoom lens block 120 includes an iris position adjustment mechanism (not depicted) for adjusting an iris amount (stop amount) of the aforementioned zoom lens and an iris DC motor 123 connected to this iris position adjustment mechanism. This iris DC motor 123 is connected to an iris DC motor drive circuit 145 of the camera control unit 140, so as to be operated by an iris DC motor drive voltage signal 140c outputted from this drive circuit 145.
Still further, the zoom lens block 120 includes a zoom position detecting rheostat 124 which is interlocked to be slided with a zoom position adjustment operation of the aforementioned zoom position adjustment mechanism and a focus position detecting rheostat 125 which is interlocked to be slided with a focus position adjustment operation of the aforementioned focus position adjustment mechanism.
On the other hand, the camera control unit 140 includes, as shown in FIG. 2: an operation section 141, a control section 142, a zoom DC motor drive circuit 143, a focus DC motor drive circuit 144, an iris DC motor drive circuit 145, an A/D converter 146, 147, a position detecting power circuit 148, and a position data storage section 149. This camera control unit 140 is installed, for example, in a building manager room which is separated from the location of the aforementioned camera unit 110.
The operation section of the camera control unit 140 is provided with a zoom position adjustment knob 141a, a focus position adjustment knob 141b, an iris position adjustment knob 141c, a position store key 141d, and a preset key 141e. These adjustment knobs 141a, 141b, and 141c, and the keys 141d and 141e are respectively connected to the control section 142. The operation section 141 is formed, for example, on an operation panel arranged in the aforementioned building manager room so that the adjustment knobs and keys can be operated by the manager or the like.
The control section 142 controls the aforementioned DC motor drive circuits 143, 144, and 145 according to the operations of the aforementioned adjustment knobs 141a, 141b, and 141c of the operation section 141.
That is, when the zoom position adjustment knob 141a is operated, the control section 142 makes the zoom DC motor drive circuit 143 output a zoom DC motor drive voltage signal 140a.
Moreover, when the focus position adjustment knob 141b is operated, the control section 142 makes the focus DC motor drive circuit 144 output a focus DC motor drive voltage signal 140b.
Furthermore, when the iris control adjustment knob 141c is operated, the control section 142 makes the iris DC motor drive circuit 145 output an iris DC motor drive voltage signal 140c.
Here, the aforementioned DC motor drive voltage signals 140a, 140b, and 140c outputted from the aforementioned DC motor drive circuits 143, 144, and 145, respectively are DC currents of positive or negative polarity within a range of .+-.12 volts so that respective voltage values to be applied to the corresponding DC motors can be varied in this range of .+-.12 volts.
When the zoom position adjustment knob 141a is operated so as to request for the zoom position in the TELE direction, the control section 142 controls so that the zoom DC motor drive circuit 143 outputs a zoom DC motor drive voltage signal 140a of positive or negative polarity. On the other hand, when the zoom position adjustment knob 141a is operated so as to request for the zoom position in the WIDE direction, the control section 142 controls so that the zoom DC motor drive circuit 143 outputs a DC motor drive voltage signal 140a of negative or positive polarity.
Moreover, when the zoom position adjustment knob 141a is operated by a large value in the TELE or WIDE direction, the control section 142 controls so as to increase the voltage of the zoom DC motor drive voltage signal 140a outputted from the zoom DC motor drive circuit 143.
It should be noted that when the focus position adjustment knob 141b or the iris position adjustment knob 141c is operated for changing the focus position or the iris position, the controls section 142 similarly control the focus DC motor drive circuit 144 or the iris DC motor drive circuit 145 so as to output a focus DC motor drive voltage signal 140b or an iris DC motor drive voltage signal of positive or negative polarity.
In the camera unit 110 shown in FIG. 1, the respective DC motors 121, 122, and 123 arranged in the zoom lens block 120 are operated according to the corresponding DC motor drive voltage signals 140a, 140b, and 140c which have been outputted as described above. For example, the zoom DC motor 121 is controlled to rotate in a direction according to the polarity of the aforementioned zoom DC motor drive voltage signal 140a and to increase its rotation speed as the voltage increases.
Consequently, in the camera unit 110, a zoom operation is carried out in the TELE or WIDE direction according to the polarity of the zoom DC motor drive voltage signal 140a, whereas the zoom position shifting speed is changed according to an increase and a decrease of a voltage of the zoom DC motor drive voltage signal 140a.
Furthermore, in the conventional image pickup system 100, the position detecting power circuit 148 in the pickup camera control unit 140 outputs a position detection DC voltage V+, V- to the zoom lens block 120 of the camera unit 110. These position detection DC voltages V+, V- are supplied, as shown in FIG. 1, to both ends of the zoom position detection rheostat 124 and the focus position detecting rheostat 125 which are connected in parallel in the zoom lens block 120.
The zoom position detecting rheostat 124 outputs a voltage (voltage divided by the rheostat) corresponding to the zoom position as a zoom position voltage signal 140e to the A/D converter 146 of the camera control unit 140. This zoom position voltage signal 140e is, as shown in FIG. 2, converted from AC to DC by the A/D converter 146 and supplied as zoom position voltage data to the control section 142.
On the other hand, the focus position detecting rheostat 125 outputs a voltage (voltage divided by the rheostat) corresponding to a focus position as a focus position voltage signal 140f to the A/D converter 147 of the camera control unit 140. This focus position voltage signal 140f is converted from AC to DC by the A/D converter and supplied as focus position voltage data to the control section 142.
The control section 142 stores the aforementioned zoom position voltage data and the focus position voltage data in the position data storage section 149 according to the operation of the position store key 141d. When the preset key 141e is operated so as to request for preset which controls the zoom position adjusting mechanism and the focus position adjusting mechanism of the camera unit 110 to be positioned at the stored zoom position and the stored focus position, the control section 142 reads out the zoom position voltage data and the focus position voltage data from the position data storage section 149 and changes the voltage values of the zoom DC motor drive voltage signal 140a and the focus DC motor drive voltage signal 140b, so that zoom position voltage data and focus position voltage data are respectively identical to the zoom position voltage data and the focus position voltage data which have been read out from the position data storage section 149, thus adjusting the zoom position and the focus position to be set at the preset zoom position and the preset focus position.
Moreover, the conventional image pickup system is provided with a serial communication such as RS-232C for data communication with a system controller (not depicted). In such a conventional image pickup system, the zoom position, focus position, and iris position are controlled according to zoom position instruction data, focus position instruction data, iris position instruction data, zoom position and focus position storage request data, and preset request data which are supplied from the system controller.
In such an image pickup system, a single system controller is connected to a plurality of camera control units 140, enabling the control at a single center of a plurality of camera units 110 installed in a plurality of locations within an area to be monitored.
Recently, in contrast to the aforementioned conventional camera unit 110, there has been utilized a stepping motor driven camera apparatus in which zooming, focusing, and iris adjustment of the zoom lens is carried out by driving a stepping motor. The zoom lens used in such a camera apparatus costs less and has a smaller size than the zoom lens used in the conventional DC motor driven type camera unit 110. For example, such a lens has begun to be used as a built-in component in a monitor video camera, for example.
However, in such a stepping motor driven type camera apparatus, the aforementioned stepping motor is normally driven by a pulse signal generated by a microcomputer built in the apparatus, and has a control system different from the aforementioned DC current driven type camera unit 110. Consequently, in the conventional image pickup system 100, it is impossible to directly connect a stepping motor driven type camera apparatus to the camera control unit 140 intended for the DC motor driven type camera unit 110.
For this, in order to replace the camera unit 110 of the DC motor drive type in the existing image pickup system 100 with a stepping motor drive type camera apparatus, it is necessary to replace the camera control unit 140 and the aforementioned system controller, which brings about a problem requiring a large cost and engineering work. From the viewpoint of utilizing the existing facility, it has been desired to connect a stepping motor drive type camera apparatus to the camera control unit 140 intended for the conventional DC motor driven camera unit 110.